VEGFA and neoplasm: Besides sprouting, the formation of the endothelial lining of tumor vessels is promoted by cooption of neighboring preexisting vessels [36], intussusception (insertion of connective tissue columns into vessel lumen), glomeruloid angiogenesis, as well as VEGF-induced recruitment of highly proliferative circulating endothelial cells (CECs) and endothelial progenitor cells (EPCs) from the BM, hematopoietic stem cells (HSCs), progenitor cells, monocytes, and macrophages [37].